The present invention relates to an optical power meter and more particularly, to an optical power meter for selectively switching at least two photo detectors.
Conventionally, in the field of optical fiber communication, an optical power meter is used to measure the optical characteristics of a light emission element and the transmission characteristics of the optical signal in an optical fiber. A photoelectric conversion element such as a photodiode and a photo-transistor is provided as a photo detector of the optical power meter. The photoelectric conversion element has wavelength sensitivity characteristics according to which photoelectric conversion element responds to the wavelengths corresponding thereto. Since the wavelength sensitivity characteristics of the photoelectric conversion element are fixed, light having a wavelength outside the region of the sensitivity characteristics cannot be detected. The characteristics of wavelength sensitivity can cover only a narrow region of the spectrum. To measure power of the optical signals over a wide wavelength region, a plurality of photoelectric conversion elements must be provided of which respective wavelength sensitivity characteristics can cover only limited parts of the wide wavelength range. Depending on these parts of the wavelength region, an appropriate one of the plurality of photoelectric conversion elements must be selected and exchanged. Thus, the measurement of optical power becomes troublesome.